Recommendation ITU-R M.2057-0
(02/2014)
Systems characteristics of automotive
radars operating in the frequency
band 76-81 GHz for intelligent
transport systems applications
M Series
Mobile, radiodetermination, amateur
and related satellite services
ii
Rec. ITU-R M.2057-0
Foreword
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Electronic Publication
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Rec. ITU-R M.2057-0
1
RECOMMENDATION ITU-R M.2057-0
Systems characteristics of automotive radars operating in the frequency band
76-81 GHz for intelligent transport systems applications
(2014)
Scope
This Recommendation specifies the system characteristics of automotive radars operating under the
radiolocation service in the frequency band 76-81 GHz. These technical and operational characteristics
should be used in compatibility studies between automotive radars operating in the radiolocation service and
systems operating in other services.
The ITU Radiocommunication Assembly,
considering
a)
that antenna, signal propagation, target detection, and large bandwidth characteristics for
automotive radars are needed to optimally achieve their functions in certain frequency bands;
b)
that the technical characteristics of radars operating in the radiodetermination service are
determined by the needs of the system and may vary widely from band to band;
c)
that representative technical and operational characteristics of systems operating in
frequency bands allocated to the radiodetermination service are necessary to determine the
feasibility of introducing new types of systems;
d)
that procedures and methodologies are needed to analyse compatibility between radars
operating in the radiodetermination service and systems operating in other services,
recommends
that the systems characteristics for automotive radars operating in the frequency band 76-81 GHz
for intelligent transport systems (ITS) applications as described in the Annex should be used for
sharing/compatibility studies.
2
Rec. ITU-R M.2057-0
Annex
Systems characteristics of automotive radar systems operating in
the frequency band 76-81 GHz for ITS applications
1
Introduction
In the frequency band 76-81 GHz, radar systems in support of enhanced road safety are operated.
Evolving demands related to automotive safety applications, including the reduction of traffic
fatalities and accidents require a range resolution for automotive radar systems leading to a
necessary bandwidth of up to 4 GHz.
2
Technical characteristics of automotive radar systems operating in the frequency
band 76-81 GHz
Regarding functional and safety requirements, the automotive radar systems operating in the
76-81GHz range can be separated in two categories:
–
Category 1: Adaptive Cruise Control (ACC) and Collision Avoidance (CA) radar, for
measurement ranges up to 250 metres the typical technical characteristics are listed in
Table 1 as Radar A. For these applications, a maximum continuous bandwidth of 1 GHz is
required. Such radars are considered to add additional comfort functions for the driver,
giving support for more stress-free driving.
–
Category 2: Sensors for high resolution applications such as Blind Spot Detection (BSD),
Lane-Change Assist (LCA) and Rear-Traffic-Crossing-Alert (RTCA), detection of
pedestrians and bicycles in close proximity to a vehicle, for measurement ranges up to
100 metres the typical technical characteristics are listed in Table 1 as Radar B, Radar C
and Radar D. For these high resolution applications, a necessary bandwidth of 4 GHz is
required. Such radars directly add to the passive and active safety of a vehicle and are
therefore an essential benefit towards improved traffic safety. The increased requirements
for active and passive vehicle safety are already reflected in the requirements for vehicle
testing. Radar E operates with a higher field of view to enable high-resolution applications
such as pedestrian detection, parking-aid, emergency braking at low speed (< 30 km/h).
The technical parameters of radiolocation radar systems operating in the frequency bands
76-77 GHz and 77-81 GHz are presented in Table 1.
Rec. ITU-R M.2057-0
3
TABLE 1
Automotive radar characteristics in the frequency band 76-81 GHz
Radar A(1)
Radar E
Automotive
high-resolution radar
Radar B
Automotive highresolution radar
Radar C
Automotive highresolution radar
For front applications
For corner applications
Radar D
Automotive
high-resolution
radar
76-77
77-81
77-81
77-81
77-81
Up to 250
Up to 100
Up to 100
Up to 100
Up to 50
Range resolution (cm)
75
7.5
7.5
7.5
7.5
Typical emission type
FMCW, Fast-FMCW
FMCW, Fast-FMCW
FMCW, Fast-FMCW
FMCW
FMCW, Fast-FMCW
Max necessary bandwidth
(GHz)
1
4
4
4
4
Chirp bandwidth (GHz)
1
2-4
2-4
2-4
2
Typical sweep time (s)
10 000-40 000 for
FMCW
10-40 for fast-FMCW
10 000-40 000 for
FMCW
10-40 for fast-FMCW
10 000-40 000 for
FMCW
10-40 for fast-FMCW
2 000-20 000 for
FMCW
10 000-40 000 for
FMCW
10-40 for fast-FMCW
Maximum e.i.r.p. (dBm)
55
33
33
45
33
Maximum transmit power to
antenna (dBm)
10
10
10
10
10
Max power density of
unwanted emissions
(dBm/MHz)
0 (73.5-76 GHz and
77-79.5 GHz)
–30 otherwise
–30
–30
–13(2)
–30
Receiver IF bandwidth
(–3 dB) (MHz)
0.5-1
10
10
10
10
Receiver IF bandwidth
(–20 dB) (MHz)
0.5-20
15
15
15
15
Automotive radar
Parameter
Sub-band used (GHz)
Typical operating range (m)
For front
applications for e.g.
for adaptive cruise
control
Very short range
applications (e.g.
parking-aid, collision
avoidance at very low
speed)
4
Rec. ITU-R M.2057-0
TABLE 1 (end)
Radar A(1)
Radar E
Automotive
high-resolution radar
Radar B
Automotive highresolution radar
Radar C
Automotive highresolution radar
For front applications
For corner applications
Radar D
Automotive
high-resolution
radar
–115
–120
–120
–120
–120
Receiver noise figure (dB)
15
12
12
12
12
Equivalent noise bandwidth
(kHz)
25
16
16
16
16
Typical 30,
Maximum 45
TX: 23
RX: 16
TX: 23
RX: 13
TX: 35 max.
RX: 35 max
TX: 23
RX: 13
0.3-1 above road
0.3-1 above road
0.3-1 above road
0.3-1 above road
0.3-1 above road
Antenna azimuth scan angle
(degrees)
TX/RX: ±15
TX: ±22.5
RX: ±25
TX: ±23
RX: ±30
TX: ±30
RX: ±30
TX: ±50
RX: ±50
Antenna elevation HPBW
(degrees)
TX/RX: ±3
TX/RX: ±5.5
TX/RX: ± 5.5
TX/RX: ± 5.5
TX/RX: ± 5.5
Automotive radar
Parameter
Receiver sensitivity (dBm)(3)
Antenna main beam gain
(dBi)
Antenna height (m)
(1)
(2)
(3)
For front
applications for e.g.
for adaptive cruise
control
Radar type A is related to Recommendation ITU-R M.1452.
Maximum power density of unwanted emission is specified at antenna input terminal.
The receiver sensitivity is determined using the equivalent noise bandwidth.
Very short range
applications (e.g.
parking-aid, collision
avoidance at very low
speed)
Rec. ITU-R M.2057-0
3
5
Operational characteristics of automotive radar systems operating in the frequency
bands 76-77 GHz and 77-81 GHz
Automotive radar applications are evolving from providing additional comfort functions, such as
Adaptive Cruise Control (ACC) and Collision Avoidance (CA) radar, to functions that significantly
add to the passive and active vehicle safety. This requires systems that can detect objects in the
close proximity (in the order of 15 metres) of the vehicle, such as pedestrians or bicycles. Such
applications require radar sensors that have a target separation capability of less than
10 centimetres. Radar sensors that provide this resolution require an operating bandwidth of 4 GHz.
Radar A type sensors detect the relevant road traffic in order to adapt the speed of the vehicle to that
of other vehicles ahead. To satisfy the demands for increased car safety, and depending on the
application, one or more radar A type systems may be combined with additional radar B, C, D and
E type sensors in one vehicle. Based on the sensor information, the data processing system in the
vehicle will trigger the appropriate radar.
Radar B, C, D and E type sensors cover the close proximity of a vehicle and will add additional
active and passive safety functions, e.g. autonomous emergency braking, active blind spot
assistance and lane change assistance.
4
Protection criteria
The desensitizing effect on radars operated in this frequency band from other services of a CW,
FMCW or noise-like type modulation is predictably related to its intensity. In any azimuth sectors
in which such interference arrives, its power spectral density can simply be added to the power
spectral density of the radar receiver thermal noise, to within a reasonable approximation. If the
power spectral density of the radar-receiver noise in the absence of interference is denoted by N0
and that of noise-like interference by I0, the resultant effective noise power spectral density
becomes simply I0 + N0. An increase of about 1 dB for the automotive radars would constitute
significant degradation. Such an increase corresponds to an (I + N )/N ratio of 1.26, or a protection
criterion I/N of about 6 dB.
The aggregation factor can be very substantial in the case of certain communication systems, in
which a great number of stations can be deployed. The effect of pulsed interference is more difficult
to quantify and is strongly dependent on receiver/processor design and mode of operation.
In particular, the differential processing gains for valid-target return, which is synchronously
pulsed, and interference pulses, which are usually asynchronous, often have important effects on the
impact of given levels of pulsed interference. Several different forms of performance degradation
can be inflicted by such desensitization. Assessing it will be an objective for analyses of interactions
between specific radar types.
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